In conventional hand-powered, electric-powered, and pneumatic-powered tool drivers, adjustable chucks are used for holding a tool such as a drill bit. A conventional chuck has a conical body threaded onto the drive shaft of the rotary tool. Three jaws spaced circumferentially 120.degree. apart from each other are constrained in passageways defined by the chuck body. The spacing between the jaws is adjusted by rotating an adjustment ring which encircles the chuck body. Such a chuck is keyless when the adjustment ring is rotated by hand.
Several attempts have been made to provide grip boots having high coefficients of friction for improving the user's grip on a chuck, especially a keyless chuck. For example, U.S. Pat. Nos. 5,452,906 issued to Huff et al. and 5,476,273 issued to Shadeck et al. each discuss the use of grip boots for improving the user's grip on a chuck.
One problem associated with soft grip chucks is the fact that the soft grip material is not very durable. When using a drill having a soft grip chuck to drill in a small constrained location, incidental contact of the rotating chuck with another object, such as an obstructing portion of the workpiece, may damage the soft grip material. This excessive wearing and damaging of the soft grip is very undesirable.